Thermostatically controlled grate



June 3, 1941. J. K. DU'KAS 2,244,189

THERMOSTATICALLY CONTROLLED GRATE Filed NOV. 8, 1959 www@ Patented June 3, 1941 UNITED STATES PATENT OFFICE THERMOSTATICALLY OONTROLLED GRATE James K. Dukas, Kingston, Pa.

Application November 8, 1939, Serial No. 303,488

1 Claim.

This invention relates to thermostatically controlled grates and has for one of its objects the production of a simple and efficient means for automatically discontinuing the operation of a furnace grate before the 'hot coals in the fire-box reach the grate and fall into the ash-pit.

A further object of this invention is the production of a simple and eicient means placed within the fire-box for *contact with the hot .coals within the :lire-box at a selected .position above the grate for automatically shutting-off the operation of the grate when the hot coals contact said means.

Other objects and advantages of the .present invention will appear throughout the following specification and claim.

In the drawing: k

Figure 1 is a side elevational View of a furnace, certain Iparts being shown in section 'and illustrating the position of the heat ,conducting thermostat control bar;

Figure 2 is a top plan View of a furnace, icertain parts bein-g shown in section and illustrating the position of the heat conducting bar;

Figure 3 is a vertical sectional View taken on line 3-3 of Figure 1;

Figure 4 is a perspective view of the heat conducting .bar and heavy duty thermostat; and

Figure 5 is a diagrammatic view of a modified form of the invention.

By referring to the drawing, it will be seen that I0 designates the conventional type of furnace havin-g an automatically operated grate II similar to that shown in my [previous patent relating to furnace grates, Number 2,184,292, issued December 26, 19.39. It has been found by practical experience that automatically operated grates tend to rbring -down the ashes to a point Where the hot ycoals directly contact the grates and fall into the ash-.pit thereby tending to burn out these grates. To avoid this difficulty, I have discovered that by placing a heat conducting .bar l2 within the nre-box in the manner shown in the drawing, this dillculty may be overcome. This heat conducting bar I 2 is preferably placed at a safety zone of approximately 11/2 inches above the grate I I in the ash-bed or fire-box and below the active fire, in the position shown in Figure 1.

The heat conducting bar I2 is preferably onehalf inch thick and 11/2 inches Wide, the narrow edge being uppermost in the manner illustrated in Figure 3. The bar I2 is placed transversely within the ash-bed or fire-box and one end indicated by the numeral I3 projects beyond the casing of the furnace and supports a heavy duty thermostat control I4 at its outer end, which thermostat control is connected to the wires I5 and I6 which rcontrol the grate operating mechanism II similar to that described in my previous ,patent above identified. The heavy duty thermostat which is `preferably used registers and operates =up to 200 of heat or over. The melting lpoint of iron and other similar metals is over 400. When the mechanical grates I I start to operate and reduce the ash-bed, the re within the lire-box comes into contact with the iron heat conducting bar I2, which bar becomes hot and the heat is transmitted to the outer end I3 of the bar where the thermostat is mounted and set so as to` throw olf the power through the lines I5 and I6 at a temperature of approximately 100 or 150. l l

The conventional blower usually employed in connection with an apparatus of this character works independently from this :ash-removing mechanism, and is operated .by the ordinary temperature thermostat which registers only up to or 100, yand is located in -a room in the -building which is heated by the furnace. When the temperature in the room drops, this thermostat starts the blower. However, vas the lcoal is consumed within the furnace and the ashes are accumulated in the lire-chamber, the heat conducting lbar I2 which Acarries the heavy duty thermostat I4 becomes cold -and'throws on the power of the mechanical grate shaker. The mechanical grate then starts and reduces the ashes until the fire comes into contact with the bar I2 again and the heat absorbed by the bar I2 and passing to the thermostat I4 works the thermostat I4 to operate and throw oi the power which controls the operation of the grate.

The [present device is particularly adapted. in connection with lash-removing devices where an overhead feed is employed for feeding fuel to the :furnace and it has been found that the present heat lconducting bar and the location thereof in the furnace will provide an elicient means in `conjunction with the thermostat I4 for automatically cutting off the power which operates the grates Il when the hot coals are :brought down within a predetermined distance with respect to the grate, thereby preventing the hot coals from being deposited in the ash-pit.

It should be understood that the present invention relates solely to the location of the heat conducting bar within the furnace and its relationship to the grates as Well as the thermostat which controls the cutting off of the power ried directly by the end of the bar I2 which prof jects beyond the furnace. The thermostat I4 shown is of the conventional type andfis only an example of those suitable for use in the present instance. The surface aquastat illustrated in the catalog of W. W. Grainger, Inc., Net Price Motor" Book No. 114, on page 59, printed in July of 1939, although designed to be responsive to water temperatures, may be used to advantage if desired, since the temperature of the bar will ehiciently actuate this type of acluastat In carrying out the invention, one type of arrangement may be employed such as that illustrated in Figure 1, wherein the thermostat or aquastat I4 has one side directly connected to the main power line I8 through the medium of the wire I5 and the other side of the aquastat or thermostat I@ is directly connected to the motor I9 which drives the grate-actuating-mechanism Il'. The other side of this motor IS is electrically connected to a wire leading to the pressure control and room thermostat which also leads to the power line 22. A motor 23 which actuates a blower 24 is also electrically connected to the wires I3 and 20, as shown in Figure 1.

In Figure 5, I have shown a modied form of the invention illustrating the manner in which my device maybe applied to the traveling grate type of grate wherein the traveling grate is indicated bythe numeral 25, to which fuel is fed from a hopper 26, the grate 25 depositing ashes into an ashpit 2l at the opposite end of the grate 25. A head conducting bar I2a similar to the bar I2 extends transversely across the discharge end of the traveling grate 25 and to this bar I 2a is secured a heavy duty thermostat I da, similar to that as illustrated in Figure 4. This thermostat Ida is electrically connected to a motor I9EL similar to the motor I9 which drives the traveling grate 25.

It should be understood that this device may kbe applied to any typek of grate where the fuel is fed thereto from above, and I do not desire to limit myself to the use of this heat conducting har and heavy duty thermostat in conjunction with any particular type of grate.

Certain detail changes in the mechanical construction and arrangement of parts may be employed without departing from the spirit of the invention, so long as such changes fall within the scope of the appended claim.

Having described the invention, what is `claimed as new is:

In combination with a furnace, -a grate, a heat conducting bar mounted within the fire-box and above the grate, said heat conducting bar having a projecting end extending outside andbeyond the outer wall of the furnace, a mechanical grate shaker, a thermostat carried by the projecting end of said heat conducting har at a point outside of the furnace, and means electrically connecting the mechanical grate shaker with the thermostat for controlling the operationv of the mechanical grate shaker, the heat from the fur-V nace seing adapted to travel longitudinally of the heat conducting bar toward the projecting end thereof foi` actuating the thermostat in a manner whereby the mechanical grate shaker will be rendered inactive when the temperature of the bar reaches a predetermined degree to cause the thermostat to automatically cut-ofi the current from the mechanical grate shaker and render the mechanical grate shaker inactive.

JAMES K. DUKAS. 

